Technologies for production of green hydrogen and hydrogen based synthetic fuels

Hydrogen is an essential material/fuel for industry and energy conversion. The processes for producing hydrogen depend on the raw materials and energy source used. In terms of climate impacts, the most promising hydrogen production method is water electrolysis. The regenerative electrolysis process depends on the carbon intensity of the electricity and the efficiency of converting that electricity into hydrogen. The development of technologies to extract hydrogen (from conventional and renewable resources) tends to optimise the water electrolysis process using renewable energies by extending material durability, increasing performance efficiency, and reducing precious metal contents in catalysts, thereby lowering the production costs. The article introduces the latest advances in green hydrogen production technologies using renewable energies, particularly focusing on water and seawater electrolysis, combining electrolysis and solar energy as well as hydrogen-based synthetic fuel production, hydrogen production from biomass and biogas.

Production of green hydrogen by efficient and economic electrolysis of water with super-alloy nanowire type electrocatalysts

Green hydrogen production from the electrolysis of water has good application prospect due to its renewability. The applied voltage of 1.6-2.2V isrequired in the traditional actual water electrolysis process although the the oretical decomposition potential of electrolyzing water is 1.23V. The high overpotential in the electrode reaction results in the high energy-consuming for the water electrolysis processes. The overpotentials of the traditional Ru, Ir and Pt based electrocatalysts are respectively 0.3V, 0.4V and 0.5V, furthermore use of the Pt, Ir and Ru precious metal catalysts also result in high cost of the water electrolysis process. For minimizing the overpoten tials in water electrolysis, a novel super-alloy nanowire electrocatalysts have been discovered and developed for water splitting in the present pa per. It is of significance that the overpotential for the water electrolysis on the super-alloy nanowire electrocatalyst is almost zero. The actual voltage required in the electrolysis process is reduced to 1.3V by using the novel electrocatalyst system with zero overpotential. The utilization of the super-alloy nanowire type electrocatalyst instead of the traditional Pt, Ir and Ru precious metal catalysts is the solution to reduce energy consumption and capital cost in water electrolysis to generate hydrogen and oxygen.

Removal of Heavy Metal Mercury (Hg) Liquid Waste through Electrolysis Method in Paya Ateuk Village, Pasie Raja District, South Aceh

Electrolysis is one of the methods used to remove heavy metal mercury (Hg). The electrolysis process is carried out on residual liquid waste from gold processing by utilizing chemical reactions through electrodes immersed in an electrolyte solution. This research method is experimental. We conducted laboratory tests to see the electrolysis process on the residual liquid waste from gold processing in a 10-liter container. We took samples from 10 different containers, 1 liter each from each tub. Sampling time was carried out in the morning, afternoon, and evening. The results showed a significant decrease in mercury (Hg) levels up to 1.30% with 12 volts of electricity for 100 minutes. In contrast, the lowest decrease occurred in the electric current of 3.3 volts within 25 minutes. We use the electrolysis method. This heavy metal removal technique can be applied and managed properly by the community and local government to minimize heavy metal pollution such as mercury in the surrounding environment due to waste from the community's traditional gold processing.

Impact of Different Electrolytes on the Machining Rate in ECM Process

Electrochemical machining is a nonconventional machining process in which the metal removal is achieved by the electricity and chemical solution known as an electrolyte. It is the reverse electrolysis process where the application of electricity facilitates the current travel in between anode and cathode. The mechanism of the ion movement is similar to the electrolysis process. Electrochemical machining (ECM) is a type of advanced machining process which employs electricity to perform the machining process on the workpiece. It is also known as a reverse electroplating process where metal removal is achieved instead of metal deposition on the metal surface. There are various parameters that affect the metal removal process in the ECM process, such as electrolyte, power supply, workpiece material, and tool material. The electrolyte is one of the key factors impacting the machining rate, surface finish, and reliability of the produced parts. In this project, a brief study is carried out regarding the electrochemical process and the electrolytes where the properties, functions, merits, and demerits are evaluated. The impact of the various electrolytes and their suitability for machining of various metals is also discussed. The findings of the effect produced by using the mixture of the electrolyte in the electrochemical machining process are discussed in this project. The effects of the complexing agents on the electrolyte and the electrochemical process as a whole are also reviewed.

Stainless Steel Cyclic Voltammograms in Dioscorea Opposita Flour Media

Improving the efficiency of hydrogen gas production in the water electrolysis process draws great attention from many scholars. To improve the efficiency of the process and reduction in the cost, stainless steel has been widely implemented in the industrial water electrolysis process. Electrolyte modification is also one of the methods to improve the water electrolysis process. The study used Dioscorea opposita tuber flour as a media addition in an alkaline solution. The efficiency of water electrolysis was evaluated by cyclic voltammetry. The result showed that the activity of the electrode and energy consumption were increased with values of 29 and 23%, respectively, by adding 3 g of the media. However, no media addition showed the lowest energy consumption regarding overpotential value. In general, the Dioscorea opposita tuber flour tends to cover the electrode and reduce the activity. Moreover, the utilization of wastewater from Dioscorea opposita flour industry is still beneficial to produce hydrogen gas instead of using freshwater.